Solubilized azo dye



ing further substituents to the molecule.

ansactive methylene or methenyl group Patented Oct. 17, 1950 UNITED 's'rA'r SOLUBILIZED AZO DYE Marvin H. Gold and Harold H. Levine; Chicago, 111., assignors toThe Visking Corporation," Chicage, 111., a corporation of Virginia No Drawing. Application December 20, 1946,

Serial N0. 717,612 1 I i 1 Claim. (01. 260-144) 'I'his invention relates to dyes, and to the method of preparing the same. More particu larly, it relates to new solubilized dyes, and to a newand improved method for producing the same.

In the dye industry, solubility. characteristics "dyes, aswell as such solubili'zed dyes.

Another object of this invention'is to provide a method wherein the sulfonation of the aromaticnucleus to improve solubility is avoided.

Other and additional objects of this invention will become apparent hereinafter. I I

In general, the objects of this invention are p shed bycoupling a diazotized or a polyidiazotized aromatic amine with a water-soluble sulfonate containing an activated methylene fonatesrof beta-nitro alkanes,

In 'sulfonates; of. beta-nitro alkanes the methyleneor methenyl group is said to be activated,

dueto the fact that the activating group, i. e., nitro. group, isdirectly attached to, the carbon atom of? the said methylene or methenyl. group.

- Y water-soluble sulfonate .ofa beta-nitro alkane in which. thenitro, group is directly attached: tothe methylene o'rj methenyl -group in the chain can be used. Such sulfonatescanbe prepared by the method disclosed in copending application Serial No. 617,929, filed September 121,: 1945, now Patent No. 2,510,281, issued June The. following are'illustr'ative specific exam- .plesaof 'beta-nitro alkane sulfonates containing which can be used in the process:. v

Ammonium-z nitroethane l-s'ulfonate ""Ammoriium l' nitropropanesulfonate 'Potassium-2-nitrobutane-l-sulfonate" "Sodium-Z' nitropropane-l-sulfonate. S'odium- 2 -phenyl.- 2 -nitroethane 1 -sulfonat Ammonium-12-nitrododecane-l-sulfonate Any diazonium or polydiazonium (such as tetrazonium) compound which in the reaction The coupling occurs by forms a stable coupled product can be used in the process. Diazotized p-toluene nitroaniline, diazotized benzidine, diazotized p-amino azobenzene, tetrazo'tized ber i-zidine diazotized 2-arnir'io- 5-azotoluene, and diazotized alpha-naphthyL- amine are a few illustrative examples of diazoni um and polydiazoniiim compounds which can be used in the process. I i 1 y replacement of. a hydrogen atom on the activated methylene o menyl carbon, as is represented by the following equation showing the reaction. of phenyl diazonium chloride with ammonium-Z-nitrobutanel-sulfonate:

I|\TO2 minivan-o1 o'zrizon-oiiisom al IQ'Oz cgngNeN o ornsomm As is shown by the above equation,- the reaction takes place when the reactants are present in stoichiometric proportions. The reaction will also take placev when either reactantis in: excess of its stoichiometric requirements. In, practice, an excess of the activated sulfonate is preferred in order to insure complete reaction with the less readily prepared diazonium compounds.

In general, the reaction is more successful when carried out under non-acid conditions, such as neutral or preferably slightly alkaline conditions. The desired conditions are obtained by the use: of; appropriate buffer, which neutralizes the acidity'of thediazonium solution and maintains an alkaline reaction medium, or by additions to the reaction medium of an alkaliin" an amount sufficient to maintain the reaction medium on the alkaline side. I

unless otherwise specified;

The coupling reaction is. preferably .carried .out at a temperature between room temperature (20 C.) and 50 C. However, the coupling reaction can be effected ata temperature as low as 10C. or as high as '70" C.

The details and manner of practicing the invention will becom apparent by reference to the following specific examples, it beingunderstood that these examples are merely illustrative embodiments of the invention and that the scope of the invention is not limitedthereto. Throughout the examples the proportions are by weight ramble 1'1.

- A slurry ofp-nitroaniline in 200 cc. water and 2 ydrochloric acid was-diazctized by'addf 3 ing 7.2 g. Sodium nitrite at 15 C. When diazotization was complete, excess nitrous acid was destroyed with sulfamic acid and the solution filtered. The filtrate was then rapidly added to 28 g. of ammonium-Z-nitropropane-1-sulfonate and 25 g. of sodium acetate in 200 cc. water at room temperature. .An orange precipitate of self-coupled product formed while stirring overnight. This was removed by filtration, and the filtrate saturated with sodium chloride, whereupon a canary yellow product was precipitated and it was extracted with methanol, in a Soxhlet extractor to remove the product from inorganic salts and further purified by recrystallization from a benzene-methanol mixture. Upon analysis, the product was identified as sodium-2-nitro-2-(p-nitrobenzeneazo) propane-l-sulfonate.

C9H9N4O'1SNaZ Na, Found: Na, 6.2%; S, 7.9%. was water-soluble and dyed silk -Analysis calculated for 6.8%; S, 9.4%.

The product yellow.

-- Example 2 i complete, the product was thrown out of solution by the addition of sodium chloride. A gummy precipitate formed which hardened upon cooling to 10 C. The material was filtered, dried and then extracted in a Soxhlet extractor with methanol to separate it from inorganic salts. Concentration of the methanol solution and fractional crystallization gave two products, A and B. Fraction A was determined to be disodium- 2-(p'-2-(-2-nitropropyl 1 sulfonate) -p-azodiphenyl) -2-nitropropane-l-sulfonate.

lTIQz 17102 mms-cm-oOO-mrr-c-cmsoma Analysis calculated for C1sHisN4010S2Na2: Na, 8.2%; S, 11.4%; N, 10.0%. Found: Na, 8.2%; S, 10.7%; N, 9.4%. 7

This was an orange-brown water-soluble material which dyed silk a yellow orange.

Fraction B was determined to be sodium-2-p- (p' hyroxydiphenyl) azo-Z-nitropiopane-l-sulfonate,.a water-soluble orange-brown dye which dyed silk a yellow-orange.

Analysis calculated for C15H14N3O6SNa: Na, 5.9%; S, 8.3%; N, 10.9%. Found: Na, 6.6%; S,

' Example 3 A slurry of 9.9 g. p-aminoazobenzene, 30 cc. concentrated hydrochloric acid, and 200 cc. water was diazotized at C. After removal of excess nitrous acid with sulfamic acid, the diazonium solution was added at 0 C. to 20.5 s. of

- nitrite.

88% H acid (l-amino-8-naphthol-3,6-disulfonic acid) dissolved in water and sodium hydroxide The pH was constantly checked to maintain alkalinity by addition of sodium hydroxide as needed. This gave a deep purple solution of dye. This material was further diazotized at 0 C. by neutralizing the solution and adding cc. excess concentrated hydrochloric acid and sodium The excess nitrous acid was destroyed with sulfamic acid and the solution added at room temperature to 10 g. ammonium-Z-nitrobutane-l-sulfonate dissolved in 200 cc. water and made alkaline with sodium hydroxide. The solution was kept alkaline by periodic additions of sodium hydroxide as needed. This gave a very intense purple solution from which no product could be precipitated by the addition of salt or acidification. After the first coupling, the prod uct was readily precipitated upon the addition .of acid but, after coupling with the nitrosulfonate, the solubility had been enhanced to such a degree that it could no longer be precipitated. This solution of soluble dye gave the following stable colors with various fibers:

Cotton Amethyst Wool Light voilet Aralac Light voilet Silk Violet Raw silk Very deep purple Rayon Bright violet Example 4 Raw silk Bright orange Nylon-"n Yellow-orange Acetate rayon Bright golden orange Example 5 A slurry of 7.2 g. alpha-naphthylamine, cc. concentrated hydrochloric acid'and 200 cc. water was diazotized at 5 C. with 3.6 g. sodium nitrite. After removal of excess nitrous acid with sulfami'c acid, the solution was filtered and added at 50C. to 10 g. ammonium 2-nitrobutane-1-sulfonate in 200 cc. water. The solution was kept alkaline by periodic additions of sodium hydroxide as required. Coupling was 'very rapid, and the result- .ing solution dyed silk directly to a bright golden orange.

Example 6 mate. The dyegavevarious shades with the following fibers: l

Nylon 'i 'Reddish-orange Rayon Orange gold Aralac .Orange tan "Acetate rayon ..Pale gold Raw silk". s s -.Bri1liant copper one-l-sulfonate.

Example 7 A slurry of 6.8 g. p-nitroaniline, 15 cc. concentrated hydrochloric acid and 100 cc. water was diazotized with 3.6 g. sodium nitrite at 5-10 C. and the excess nitrous acid removed with sulfamic acid. The diazonium solution was coupled at room temperature with potassium butan-3- The resulting dye solution dyed various yarn swatches in the following shades:

Nylon Light orange Acetate rayon .Go1den brown Raw silk .Bright orange In the claims, the term diazotized is intended to cover not only diazotized compounds but also thereof, this invention is not restricted thereto 20 except as set forth in the appended claim.

We claim:

A solubilized azo dye wherein the azo group is directly bonded to the group in the chain of a beta-nitro alkane sulfonate to which the nitro group is also directly bonded.

MARVIN H. GOLD. HAROLD H. LEVINE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,251,921 Dickey et al Aug. 12, 1941 2,310,181 Mackenzie Feb. 2, 1943 2,366,633 Long Jan. 2, 1945 2,392,167 Long Jan. 1, 1946. 2,392,611 Nygard et a1 Jan. 8, 1946 2,396,917 Hanford Mar. 19, 1946 2,441,800 Degering May 18, 1948 

